The pressure at which typical gas distribution systems supply gas may vary according to the demands placed on the system, the climate, the source of supply, and/or other factors. However, most end-user facilities equipped with gas appliances such as furnaces, ovens, etc., require the gas to be delivered in accordance with a predetermined pressure, and at or below a maximum capacity of a gas regulator that may be installed in the system. Such gas regulators are implemented into these distribution systems to ensure that the delivered gas meets the requirements of the end-user facilities. Conventional gas regulators generally include a closed-loop control actuator for sensing and controlling the pressure of the delivered gas.
In addition to a closed loop control, some conventional gas regulators include a relief valve. The relief valve is adapted to provide over pressure protection when the regulator or some other component of the fluid distribution system fails, for example. Accordingly, in the event the delivery pressure rises above a predetermined threshold pressure, the relief valve opens to exhaust at least a portion of the gas to the atmosphere, thereby reducing the pressure in the system.
FIGS. 1 and 1A depict one conventional gas regulator 10. The regulator 10 generally comprises an actuator 12 and a regulator valve 14. The regulator valve 14 defines an inlet 16, an outlet 18, and a throat 11. The inlet 16 is for receiving gas from a gas distribution system, for example. The outlet 18 is for delivering gas to an end-user facility such as a factory, a restaurant, an apartment building, etc. having one or more appliances, for example. Additionally, the regulator valve 14 includes a valve port 36 carried by the throat 11 and disposed between the inlet 16 and the outlet 18. Gas must pass through the valve port 36 to travel between the inlet 16 and the outlet 18 of the regulator valve 14.
The actuator 12 is coupled to the regulator valve 14 to ensure that the pressure at the outlet 18 of the regulator valve 14, i.e., the outlet pressure, is in accordance with a desired outlet or control pressure. The actuator 12 is therefore in fluid communication with the regulator valve 14 via a valve mouth 34 and an actuator mouth 20. The actuator 12 includes a control assembly 22 for sensing and regulating the outlet pressure of the regulator valve 14. Specifically, the control assembly 22 includes a diaphragm 24, a piston 32, and a control arm 26 having a valve disc 28. The conventional valve disc 28 includes a generally cylindrical body 25 and a sealing insert 29 fixed to the body 25. The diaphragm 24 senses the outlet pressure of the regulator valve 14. The control assembly 22 further includes a control spring 30 in engagement with a top-side of the diaphragm 24 to offset the sensed outlet pressure. Accordingly, the desired outlet pressure, which may also be referred to as the control pressure, is set by the selection of the control spring 30.
The diaphragm 24 is operably coupled to the control arm 26, and therefore the valve disc 28, via the piston 32, controls the opening of the regulator valve 14 based on the sensed outlet pressure. For example, when an end user operates an appliance, such as a furnace that places a demand on the gas distribution system downstream of the regulator 10, the outlet flow increases, thereby decreasing the outlet pressure. Accordingly, the diaphragm 24 senses this decreased outlet pressure. This allows the control spring 30 to expand and move the piston 32 and the right-side of the control arm 26 downward, relative to the orientation of FIG. 1. This displacement of the control arm 26 moves the valve disc 28 away from the valve port 36 to open the regulator valve 14. So configured, the appliance may draw gas through the valve port 36 toward the outlet 18 of the regulator valve 14, as demand may be required for operation.
FIG. 1A depicts the conventional valve port 36 of the conventional regulator 10. The valve port 36 generally includes a housing 60, a cartridge 62, and a spring 64. The cartridge 62 is slidably disposed within the housing 60 such that the valve port 36 is adapted for providing both a primary seal and a back-up, or secondary, seal, as will be described. The spring 64 biases the cartridge 62 into the position depicted in FIG. 1A, which corresponds to the valve port 36 providing the primary seal.
The housing 60 includes a hollow, generally cylindrical housing having a hexagonal nut portion 66, a body portion 68, and a curtain portion 70. The body portion 68 includes an internal bore 74 defining a step 76 and a ring-shaped recess 78. The ring-shaped recess 78 contains an o-ring 83 for providing a pneumatic seal between the housing 60 and the cartridge 62. The body portion 68 further includes a plurality of external threads 72 for being threadably coupled into the regulator valve 14, as depicted. The nut portion 66 of the housing 62 is therefore adapted to be engaged by a tool such as a pneumatic ratchet to install the valve port 36 into the throat 11 of the regulator valve 14. The curtain portion 70 includes a plate 80 spaced from the body portion 68 of the housing 62 by a pair of legs 82. The plate 80 carries a secondary seat 71 including a rubber surface 73, for example. So configured, the curtain portion 70 defines a pair of windows 84 in the housing 60. The windows 84 allow for the flow of gas into the valve port 36 and through the regulator valve 14.
The cartridge 62 of the conventional valve port 36 depicted in FIG. 1A includes a hollow, generally cylindrical member defining a central orifice 88 therethrough. The cartridge 62 includes a first portion 62a and a second portion 62b. A diameter of the first portion 62a is slightly smaller than a diameter of the second portion 62b. Therefore, a shoulder 86 is disposed between the first and second portions 62a, 62b. The shoulder 86 abuts the step 76 of the housing 60 in the depicted position, thereby limiting the displacement of the cartridge 62 in the direction indicated by the arrow A in FIG. 1A.
Moreover, the first portion 62a of the cartridge 62 includes an outlet end 90 defining an externally chamfered surface 92 and a primary seat 94. The primary seat 94 is adapted to be sealingly engaged by the valve disc 28, as depicted, to stop the flow of gas through the regulator valve 14. The second portion 62b includes an inlet end 96 defining an internally chamfered surface 98 and a seating surface 95. The seating surface 95 is adapted to engage the rubber surface 73 of the secondary seat 71 upon the primary seat 94 failing to provide an adequate seal to close the valve port 36.
For example, during use, debris or some other type of foreign material may become lodged between the valve disc 28 and the primary seat 94 when the valve disc 28 attempts to seal against the primary seal 94. Thus, the primary seal fails to stop the flow of gas through the valve port 36 and the pressure downstream of the regulator 10, i.e., the outlet pressure, increases. This increase is sensed by the diaphragm 24 which further causes the valve disc 28 to be forced toward the valve port 36. This force eventually overcomes the force of the spring 64 in the valve port 36 and displaces the cartridge 62 relative to the housing 60 in a direction opposite the arrow A. Continued displacement causes the seating surface 95 on the second portion 62b of the cartridge 62 to engage the rubber surface 73 of the secondary seat 71 carried by the plate 80 of the curtain portion 70. So configured, the secondary seat 71 of the cartridge 62 seals the inlet end 96 and blocks the flow of gas from passing through the windows 84 in the housing 60, thereby preventing gas from flowing through the regulator valve 14. Moreover, the o-ring 83 seals any path for gas to penetrate the windows 84 and leak between the cartridge 62 and the housing 60 of the valve port 36. Once a downstream demand is placed back on the system however, the diaphragm 24 senses a decrease in outlet pressure and moves the valve disc 28 away from the valve port 36. The spring 64 biases the cartridge 62 back to the position depicted in FIG. 1A and any debris previously lodged between the valve disc 28 and the primary seat 94 likely releases and flows downstream of the regulator valve 14. Thus, the conventional regulator 10 and the conventional valve port 36 provide a secondary seal to back-up any failure or obstruction with the primary seal.
Additionally, as mentioned above, the conventional regulator 10 depicted in FIG. 1 further functions as a relief valve. Specifically, the control assembly 22 includes a relief spring 40 and a release valve 42. The diaphragm 24 includes an opening 44 through a central portion thereof and the piston 32 includes a sealing cup 38. The relief spring 40 is disposed between the piston 32 and the diaphragm 24 to bias the diaphragm 24 against the sealing cup 38 to close the opening 44, during normal operation. Upon the occurrence of a failure such as a break in the control arm 26, for example, the control assembly 22 is no longer in direct control of the valve disc 28 and the inlet flow will move the valve disc 28 into an extreme open position. This allows a maximum amount of gas to flow into the actuator 12. Thus, as the gas fills the actuator 12, pressure builds against the diaphragm 24 forcing the diaphragm 24 away from the sealing cup 38, thereby exposing the opening 44. The gas therefore flows through the opening 44 in the diaphragm 24 and toward the release valve 42. The release valve 42 includes a valve plug 46 and a release spring 54 biasing the valve plug 46 into a closed position, as depicted in FIG. 1. Upon the pressure within the actuator 12 and adjacent the release valve 42 reaching a predetermined threshold pressure, the valve plug 46 displaces upward against the bias of the release spring 54 and opens, thereby exhausting gas into the atmosphere and reducing the pressure in the regulator 10.
One consideration in selecting a regulator for use in a particular application includes maximizing flow capacity at the set outlet, or control, pressure. However, due to structural constraints, the conventional valve port 36 is limited as to how large of a diameter the orifice 88 may have. For example, one conventional embodiment of the valve port 36 may include an orifice 88 with a maximum diameter of seven-eighths of an inch, i.e., ⅞″.
For example, the dimensions of the housing 60 of the valve port 36 are oftentimes prescribed by the amount of torque used to install the valve port 36 into the regulator valve 14. Specifically, as mentioned above, the valve port 36 may be installed with a pneumatic ratchet. If the sidewall of the body portion 68 of the housing 60 adjacent to the threads 72 is too thin, then the torque generated by the pneumatic ratchet may shear the housing 60. Accordingly, the thickness of the housing 60, which impacts the diameter of the orifice 88 in the cartridge 62, and therefore the maximum flow capacity, is limited based on the prescribed thickness of the sidewall of the housing 60. Additionally, as described above, the conventional port 36 requires the recess 78 in the housing 60 for accommodating the o-ring 83, which prevents leakage when utilizing the secondary seal. The position and geometry of the recess 78 may further compromise the structural integrity of the sidewall of the housing 60, and therefore, must be considered in designing the thickness of the housing 60.
Moreover, to maximize flow capacity of the valve port 36, the windows 84 must be positioned substantially within the flow of gas from the inlet 16. Thus, housing 60 of the valve port 36 is dimensioned such that the curtain portion 70 and the plate 80 carrying the secondary seat 71 extend well beyond the throat 11 of the regulator valve 14. So configured, the cartridge 62 must be suitably dimensioned to slide from the position depicted in FIG. 1A to a position where the seating surface 95 is in engagement with the secondary seat 71 upon the occurrence of a failure, as described above. Such dimensions add to the size and cost of the overall valve port 36.